Self-equalizing support for doctor blades



y 1963 E. R. LJUNGQUIST ETAL 3,088,156

SELF-EQUALIZING SUPPORT FOR DOCTOR BLADES Filed April 26, 1962 2 Sheets-Sheet 1 I ,H II III IIIIIMIIHIIIP INVENTORS ERNST R.LJUNGQUIST ROGER E. BEDARD ATTORNEY y 1963 E. R. LJUNGQUIST ETAI. 3,088,156

SELF-EQUALIZING SUPPORT FOR DOCTOR BLADES Filed April 26, 1962 2 Sheets-Sheet 2 mum \ HII II I i l l I h,

uh! I HI INVENTORS ERNST R. LJUNGQUIST ROGER E. BEDARD I Mf% ATTORNEY Uited Stats 3,088,156 SELF-EQUALIZING SUPPORT FGR DOCTOR BLADES Ernst Roland Ljungquist, Worcester, and Roger Edgar Bedard, West Boylston, Mass., assignors to Lodding Engineering Corporation, Auburn, Mass, a corporation of Massachusetts Filed Apr. 26, 1962, Ser. No. 190,494 12 Claims. (Cl. 15-25653) This invention relates to a means for mounting a doctor blade so as to cause it to apply constant pressure to the surface which the doctor blade engages, and including a mounting mechanism which is self-aligning with reference to the doctor blade and the surface which is being acted upon, such as for instance a machine roll.

In carrying out the present invention, the blade is mounted upon a doctor back which is non-pivoting, contrary to the usual construction, the back being mounted at its ends upon slides guided by ways which extend generally at a right angle to the edge of the doctor blade and also at a right angle to the roll upon which the blade is to operate, the slides being rectilinearly traveled in both directions by means of a piston and cylinder arrangement utilizng the shop air at one side thereof to back off the blade away from the surface being doctored, in combination with a combined hydraulic and pneumatic system or hydropneumatic intensifier which is applied to the other end of the cylinder to move the doctor blade toward the surface doctored, :the hydraulic fluid of the intensifier ensuring constant pressure at both ends of the doctor back for applying constant pressure of the blade across the roll, and also preventing unwanted reverse motions of the slides under bumpy conditions, so that the hydropneumatic intensifier holds the blade in the desired position with equal pressure at the ends of the blade and causes the blade to be self-aligning with relation to the roll operated upon, the pneumatic system and the hydropnuematic intensifier being coupled to a four-way valve so that it is only necessary to throw the valve in one direction to cause the doctor to retreat from the roll and in the other direction to cause the hydropneumatic intensifier to bring the doctor back adjacent the roll or other surface, with the blade bearing thereon.

Other objects of the invention include the provision of various improvements in the apparatus described above including the fact that the slides comprise plates loosely mounted in the ways so that the entire doctor back can align and adjust itself under the hydropneumatic pressure; and also the ways guiding the slide plates are pivotally mounted so as to further accommodate the selfalignment action of the device in a direction generally normal to the travel of the plates, whereby the action is extremely smooth and no binding is possible.

The invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly set forth in the appended claims.

Reference is to be had to the accompanying drawings, in which FIG. 1 is a view in side elevation showing one end of the device;

FIG. 2 is a View in rear elevation thereof, looking in the direction of arrow 2 in FIG. 1, parts being in section;

FIG. 3 is a top plan view, looking in the direction of arrow -3 in FIG. 1;

FIG. 4 is an end view on an enlarged scale showing the details of the slide assembly;

FIG. 5 is a side elevation, looking in the direction of arrow 5 in FIG. 4 showing the slide assembly;

FIG' 6 is a top plan view, looking in the direction of arrow 6 in FIG. 5, and

FIG. 7 is a diagram of the hydropn'eumatic system.

Referring now to FIGS. 1, 2 and 3, there is there represented the general framework of the machine at 8 including any kind of supporting means for longitudinal bars spaced from the floor. On these bars there is provided a journal (not shown) but mounted on the stringers 10 in position to journal a roll 12.

The doctor blade itself is indicated at 16 and this is mounted more or less in the usual way on a blade holder 18. The blade holder 18 is in turn rigidly mounted on the doctor back which is indicated generally at 2! This doctor back is prefer-ably made in the form of a relatively large hollow tube which may be provided with welded partitions or the like as at 22, 22 together with circular end plates 24.

The partitions '22 and end plates 24 are centrally apertured for the slide fit reception of journals 26, 26, these being the same at both ends of the doctor back sides of the machine (see FIGS. 2 and 3) but of course providing rights and lefts.

CF-ixedly mounted on the journals 26 are plates 28, 23, these being provided with a circular series of arcuate shaped slots 30 (see FIG. 1) receiving bolts 32 threaded into the end plates 24- for holding the doctor back in angul-arly adjusted position relative to journals 26.

Journals 26 are fixedly mounted in blocks 34 which have adjustment slots 35, there being a block at each end of the doctor back, i.e., one for each journal 26, 26, these blocks being adjustably secured on slide plates 36, 36 (see particularly FIGS. 4, 5 and 6) by bolts extending through the slots 35. The slide plates are slidingly mounted in ways generally indicated at 38 and include hold-down track members 46 bolted to the ways and providing for rectilinear sliding of the slide plates without variation in a vertical direction. However, the slide plates 36 are slightly narrower than the distance between the vertical slide guiding portions 42, 42 of the ways 38, so that the slide plates 36 can move slightly from sideto-side during their rectilinear motion forward and back. As the slide plates move, the blocks 34 move with them and therefore the doctor back and the doctor blade thereon move rectilinearly back and forth relative to the surface to be doctored, i.e., the roll 12.

The means for moving the slide plates back and forth consists of cylinders 44 which in this case are fixed to the respective slide plates to move, there being a fixed piston in each cylinder as at 46. Each piston is mounted on a rod 48. The rods 48 are conveniently held in fixed position relative to the ways by means of a pair of studs 59 on the ways, the studs extending inwardly toward each other and holding between them the rod end 52 which is in the form of an eye having a rod 54 passing through it, the rod 54 being located in the studs. The cylinder construction can be of any general well known description, being provided at its ends with ports at 55, 56 for the reception of the pneumatic and hydraulic lines to be described. The ends of the cylinders opposite the rods 48 can be fastened to the respective slide plate 36 by any desired means such as for instance brackets 58 secured to the slide plate and depending therefrom, these brackets being spaced and holding between them a rod 60 upon which an end of the cylinder 44 is fastened. Thus it will be seen that pressure entering the fitting at 55 will cause the cylinder and slide plate to move to the left in FIG. 6 and pressure entering at 56 will cause the opposite motion.

The ways 38 include end plates 64, 64 which are apertured and reamed at 66 to receive fore-and-aft studs 68 appropriately mounted on a base member generally indicated at 70 as by end plates 72 thereon so that the ways themselves including the slide plates 36, block 34, etc. are enabled to pivot slightly on the axis of the studs 68. This action combined with the loose sliding action of the plates 36 provides for automatic self-alignment of the ends of the doctor back, regardless of the angularity of the roll or surface which is being operated upon with respect to the edge of the doctor blade. The base 70 is appropriately mounted on the frame of the machine.

The ports at 55 and 56 are provided with fittings such as are shown for instance in FIG. 2 at 74, 74, and these are connected by hoses to a source of air connected directly to port 56 and a source of hydraulic fluid connected to the port 55. The pressure of the hydraulic fluid is intensified by the pressure of the air (see the diagram FIG. 7). There is a source of shop air indicated by the reference numeral 76 and this leads to a four-way valve of general conventional construction 78. The air then goes through the conduit 80 through the respective fittings 56, 56 and when the handle 82 of the four-way valve 78 is in one position, air will enter the ports at 56 causing the cylinders 44 to retract, i.e., to the left in FIGS. 1 and 7 (but to the right in FIG. 6), bringing the doctor back with it and releasing the blade from the roll 12.

Shop air is also connected through a regulator 84 through a conduit 86 to a hydropneumatic intensifier generally indicated at 88. This is a device that receives the shop air under regulated pressure and applies pressure on hydraulic fluid at 90 in a cylinder by means of a diaphragm or piston-like member 92, and the hydraulic fluid then passes through conduit 94 to the ports 55. This causes the cylinders 44 to move to the right in FIGS. 1 and 7, applying the blade to the roll under equal pressure at both ends of the doctor back by means of the hydraulic fluid which is not subject to compression within the cylinder and therefore will not permit flutter in the blade due to operating conditions which would otherwise be the case if air were used directly at both sides of the piston and the cylinders 44. Thus it is only necessary to move the valve handle 82 from the position shown in solid lines in FIG. 7 to the position shown in dotted lines in order to reverse the action of the cylinders as described.

The journals 26 are angularly fixed with relation to the blocks 34 as by a key. Plates 28 are fixed to the re spective journals 26 and the bolts 32 extend into threaded holes in the plates 24 fixed to the ends of the doctor back, so that if it is desired to change the angle of the blade holder 18 with respect to the roll surface, it is only necessary to loosen the bolts at 32 and rotate the entire doctor back with relation to the slot or plate 28. If this is done, however, it may be necessary to also adjust the longitudinal position of the block 34 with respect to its slide plate 36 by means of the bolts which extend through the elongated slots 35.

Having thus described our invention and the advantages thereof, we do not wish to be limited to the details herein disclosed, otherwise than as set forth in the claims, but what we claim is:

1. A doctor support comprising an elongated doctor back, a blade holder thereon and a doctor blade on the holder, a slide at each end of the doctor back, said slides mounting the doctor back for rectilinear motion thereof transverse to its length, means guiding the said slides in generally parallel rectilinear paths, power means for moving the slides, said power means comprising a cylinder and piston for each slide, pneumatic means applied to one end of each cylinder and hydraulic means to the opposite ends thereof for moving the doctor back in one direction under air pressure and in the opposite direction by hydraulic pressure, the hydraulic means serving to move the doctor back and its blade toward the surface to be doctored.

2. A self-aligning doctor construction comprising an elongated doctor back, a blade holder and a blade thereon, a power cylinder at each end of the doctor back connected thereto for moving the same rectilinearly in a direction at right angles to the longitudinal extent of the doctor blade, a journal at each end of the doctor back, a.

block in which each journal is mounted respectively at each end of the doctor back, the respective cylinders each being secured to a block, and means for applying pressure at either end of each cylinder.

3. The apparatus as recited in claim 2 wherein the pressure applied to one end of the cylinder is pneumatic and at the other end of the cylinder being hydraulic, the hydarulic means serving to move the doctor with the blade toward the surface to be doctored.

4. A self-aligning doctor blade construction comprising an elongated doctor back, a doctor blade holder thereon, a journal at each end of the doctor back, a block for each journal, a slide plate mounting each block, ways for the slide plates, a pneumatic cylinder connected to each slide plate, means for applying pressure to either end of each pneumatic cylinder to move the slide plates, blocks, journals, etc., rectilinearly in a direction at right angles to the general axis of the doctor back.

5. The apparatus as recited in claim 4 including means guiding the slide plates loosely to provide a lateral leeway for the slide plates so that they can move laterally transversely of the direction of reciprocation thereof.

6. The apparatus as recited in claim 4 including ways for the slide plates and means mounting the ways for a slight angular adjustment about an axis parallel to the reciprocal motion of the slide plates.

7. The apparatus as recited in claim 4 including ways for the slide plates and means mounting the ways for a slight angular adjustment about an axis parallel to the reciprocal motion of the slide plates, a base for each of the ways, studs on each base, said ways being mounted on the base by means of said studs.

8. A doctor construction comprising an elongated doctor back, a blade holder and a blade on the doctor back, a journal at each end of the doctor back, means supporting the journals at each end of the doctor back, a sliding plate mounting each said journal supporting means, means for moving said plates simultaneously in the same direction, means guiding the plates, the means for moving the plates comprising a combined pneumatic and hydraulic cylinder, and a combined pneumatic and hydraulic pressure source for said cylinder, the hydraulic fluid entering at one end of the cylinder only and the pneumatic means entering at the other end of the cylinder only so as to move the entire doctor back assembly in an operative direction by means of hydraulic fluid and in a reverse direction by means of air pressure.

9. The doctor construction as recited in claim 8 including a hydropneumatic intensifier, the pneumatic pressure source being connected to said intensifier for operating the same to increase and decrease the hydraulic pressure at the one side of the cylinder, and a valve for connecting the pneumatic pressure source alone to the opposite side of the cylinder.

10. The doctor construction of claim 8 including means on the journals securing the doctor back thereto, means to angularly adjust the doctor back relative to the journals, and means holding the journals against rotative motion.

11. The doctor construction of claim 8 including a transverse plate fixed to each journal, means on each journal plate to secure the doctor back thereto at the respective ends thereof, said last-named means providing for angular adjustment of the doctor back about its longitudinal axis relative to the journal plates.

12. The doctor construction of claim 8 including a transverse plate fixed to each journal, means on each journal plate to secure the doctor back thereto at the respective ends thereof, said last-named means providing for angular adjustment of the doctor back about its longitudinal axis relative to the journal plates, and means to adjust the journals in a direction parallel to the rectilinear 5 motion of the sliding plates.

References Cited in the file of this patent UNITED STATES PATENTS 1,812,920 Ballard July 7, 1931 10 3,026,796 Crawford Mar. 27, 1962 FOREIGN PATENTS 328,826 Switzerland May 14, 1958 

1. A DOCTOR SUPPORT COMPRISING AN ELONGATED DOCTOR BACK, A BLADE HOLDER THEREON AND A DOCTOR BLADE ON THE HOLDER, A SLIDE AT EACH END OF THE DOCTOR BACK, SAID SLIDES MOUNTING THE DOCTOR BACK FOR RECTILINEAR MOTION THEREOF TRANSVERSE TO ITS LENGTH, MEANS GUIDING THE SAID SLIDES IN GENERALLY PARALLEL RECTILINEAR PATHS, POWER MEANS FOR MOVING THE SLIDES, SAID POWER MEANS COMPRISING A CYLINDER AND PISTON FOR EACH SLIDE, PNEUMATIC MEANS APPLIED TO ONE END OF EACH CYLINDER AND HYDRAULIC MEANS TO THE OPPOSITE ENDS THEREOF FOR MOVING THE DOCTOR BACK IN ONE DIRECTION UNDER AIR PRESSURE AND IN THE OPPOSITE DIRECTION BY HYDRAULIC PRESSURE, THE HYDRAULIC MEANS SERVING TO MOVE 